Summary The aircraft alternator had recently been replaced, and the pilot decided to test fly the aircraft before taking passengers on a planned local flight. At approximately 1515 eastern daylight time the aircraft took off from runway 22, climbed to about 500 feet above ground level, turned back and flew a low pass over runway 04. It then entered the downwind leg of runway 12, flew a low pass over the runway and made a turn back toward runway 30. At some point during, or prior to the last turn, some people reported a loud pop sound. The aircraft then made a single, continuous turn to align with runway 30. Descriptions of the flight path indicated that all turns were steep; bank angle descriptions varied between 60 and 90 degrees. During the final turn the aircraft stalled, descended, and struck the ground. The aircraft was upright and nose-down at the first point of impact; it then bounced, nosed-over and came to rest inverted. The pilot died as a result of injuries received during the accident. Ce rapport est galement disponible en franais. Other Factual Information Weather conditions at the airport were reported as clear sky and calm winds, with the temperature between 24 and 26 degrees Celsius. The Cessna 150 was owned by Orillia Aviation but had recently been under lease to another aviation flying school. The aircraft was returned to Orillia Aviation on 13 August 1996. At that time, to address an electrical problem, the alternator was replaced. No other problems or discrepancies were reported. The aircraft was found, inverted, in the brush short of the threshold of runway 30. Impact marks in the soil showed that the aircraft was 94 metres from the runway when all three wheels touched down. It then bounced, nosed over and came to rest inverted, about 8 metres closer to the runway. The aircraft remained largely intact but the fuselage was broken to the left behind the baggage area. The nose landing gear strut had been bent straight backwards and the cockpit area was compressed. All flight control systems were intact and continuous. The wing flaps were found in the up position, which is contrary to the full flap position the pilot normally used for landing. The flap motor was tested and determined to have been operational at the time of the accident. The engine throttle was back at a low power or idle setting. Subsequent laboratory examination showed that the engine tachometer was indicating 2200 rpm at impact. When the engine was dismantled no defects were noted that would have prevented the engine from developing full power. However, the finger screen in the carburettor had been removed and a pipe fitting had been screwed directly into the carburettor. (It should be noted that these threads are not compatible.) It could not be determined when this had been done, but there was no contamination inside the carburettor bowl. There was no mechanical explanation for the reported pop sound. There was a small, post-crash fire that started in the engine compartment. Fuel, which was leaking from the fuel strainer bowl and the carburettor, had run along the engine tachometer cable into the cockpit area and this had caused a small amount of interior fire damage. The Cessna 150 Pilot Operating Handbook indicates that the aircraft stalls in a wings-level attitude, with flaps up, at 46-47 knots indicated airspeed. In a 60 degree bank, the aircraft will have a stall speed of 66 knots; in a 75 degree bank, the aircraft will stall at 92 knots. TSB Engineering Branch examination of the airspeed indicator determined that it was indicating 50 knots when the aircraft struck the ground. The pilot had been licenced as a private pilot since 1979, and had accumulated approximately 2,200 hours. His last aviation medical was on 9 August 1995, and he was assessed as fit for a category 3 medical. After the accident, it was learned that the pilot had been prescribed Prozac (an anti-depressant) in January 1994. This information had not been communicated to the Aviation Medical Examiner or to Transport Canada Civil Aviation Medicine. Had this information been communicated, the pilot's licence would likely have been suspended. On the day of the accident, the pilot was described as being alert and in good humour. Toxicological samples examined after the accident showed ethyl alcohol in the pilot's blood of 11 mg/100ml; by comparison, the legal limit for driving is 80 mg/100ml. Also found in the pilot's blood was fluoxetrine (Prozac) of 0.025mg/100ml and a trace of chlorpheniramine (non-prescription antihistamine/decongestant). There was no evidence of putrefaction found during autopsy. The amount of alcohol is consistent with the pilot having had at least one alcoholic drink within eight hours prior to the flight. To address the risks associated with alcohol and drug consumption, Canadian Aviation Regulation 602.03 specifies the following: within eight hours after consuming alcohol; while under the influence of alcohol; or while using any drug that impairs the person's faculties to the extent that the safety of the aircraft is endangered in any way. within eight hours after consuming alcohol; while under the influence of alcohol; or while using any drug that impairs the person's faculties to the extent that the safety of the aircraft is endangered in any way.